From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.free-electrons.com ([94.23.35.102]) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1U5zM0-0002yP-NR for barebox@lists.infradead.org; Thu, 14 Feb 2013 14:00:01 +0000 Message-ID: <511CEDD4.3020108@free-electrons.com> Date: Thu, 14 Feb 2013 14:59:48 +0100 From: Maxime Ripard MIME-Version: 1.0 References: <1360774211-10983-1-git-send-email-maxime.ripard@free-electrons.com> <1360775819-5411-1-git-send-email-s.hauer@pengutronix.de> <511CB116.8050705@free-electrons.com> <20130214113503.GN1906@pengutronix.de> In-Reply-To: <20130214113503.GN1906@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: quoted-printable Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH] Add warning above get_ram_size To: Sascha Hauer Cc: barebox@lists.infradead.org Hi Sascha, Le 14/02/2013 12:35, Sascha Hauer a =E9crit : > On Thu, Feb 14, 2013 at 10:40:38AM +0100, Maxime Ripard wrote: >> Hi Sascha, >> >> Le 13/02/2013 18:16, Sascha Hauer a =E9crit : >>> Signed-off-by: Sascha Hauer >>> --- >>> common/memsize.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/common/memsize.c b/common/memsize.c >>> index d149e41..ef6381b 100644 >>> --- a/common/memsize.c >>> +++ b/common/memsize.c >>> @@ -33,6 +33,9 @@ >>> * Check memory range for valid RAM. A simple memory test determines >>> * the actually available RAM size between addresses `base' and >>> * `base + maxsize'. >>> + * >>> + * This function modifies the RAM. Do not use it if you're running from >>> + * the RAM you are going to detect! >>> */ >> >> Actually, I don't see how it modifies the RAM, at least permanently. The >> values it erase are backed up, and there's no concurrency at barebox >> level, so we are sure that the value saved will still be the one that >> would need to be backed up at the end of the function, right? > = > Yes, it restores the values, but how do you make sure the function does > not modify the instructions you are currently executing? You need bad > luck to hit this, but sooner or later this will happen. Ah, yes, this would be nasty indeed. Is there a way to know the end address of barebox into RAM ? or the address it has been loaded to and the size of its binary, so that we can just check the part that doesn't hold barebox? Maxime -- = Maxime Ripard, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox